The present invention relates to high resolution sonar for providing topographic chart data and more particularly to high resolution sonar which provides depth information along with high spatial resolution.
Synthetic aperture techniques have long been used in radar to generate "pictures" of terrain, essentially mapping the variations in the backscattering properties of the area under observation. Such pictures, as with ordinary sidelooking sonar or radar, provide no quantitative representation of the topography of the surface being viewed. A discussion of synthetic aperture imagine systems may be had by reference to U.S. Pat. No. 4,088,978, entitled "Synthetic Aperture Side-Looking Sonar System".